Improvement in steam safety-valves



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UNITED STATES EDWARD HAMILTON, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN STEAM SAFETY-VALVES.

Specification forming part of Letters Patent No. 56,409, dated July 17, 1866. d

To all whom fit may concern:

Be it known that I, EDWARD HAMILTON, of the city of Chicago, in the county of Cook and State of Illinois, have invented a certain new and Improved Safety-Valve for Steam- Boilers; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being' had to the accompanying drawings, making a part of this specitication.

The nature ot' my invention consists in the construction of a safety-valve for steam-boilers in which the valve is held down by a spring inside of the case instead of the lever and weight ordinarily used outside, and in a novel method of adjusting the same, and in providing a means for testing it.

Figure lis a plan View of a portion detached. Fig. 2 is a top-plan view of the apparatus with the case opened. Fig. 3 is a side elevation, and Fig. I a vertical section of the saine, like letters in the various figures indicating like parts.

To enable others skilled in the art to make and use my invention, I will describe its construction and operation.

The outside shell or case, A and A', is made of iron, brass, or other suitable metal, and I prefer the globular form shown, although. it can be made to work equally as well in any other form. The lower half is cast with a tube, H, attached, which tube is inserted into the boiler in the usual manner. To the upper end ot' this tube, at the shoulders j, the valve c is fitted. This valve c is supported and held in place by the shaft F, which shat't is kept in position by the cross-barf in the tube or pipe H, through which it passes at the lower end, and at the upper it passes through the plate O centrally and up into the spring box or cylinder D about one-third the length of the cylinder. Inside of the cylinder there is a small plate, b, attached and resting upon a shoulder of the shaft, which plate b supports the lower end of the spring a.

About midway between the valve e and the small plate b, I attach to the shaft the annular projection d, and under this I place the inner end of the testing-lever Gr. This lever has for its fulcrum the shell or case A, and projects outward so as to form a handle, so that by pressing upon this lever the engineer can at all times ascertain the working condition of the valve without opening the case or shell.

On the top of the lower half or hemisphere 0f the globe I place the plate C, Figs. l and 4, and on this I place the spring cylinder or box D, which is made large enough to contain a spring, a. This spring may be either a coiled, spiral, or volute spring; and although very little, if any, steam will penetrate the box or cylinder, as it is closely attached to the plate G, it may be found advisable to galvanize or otherwise protect the spring from corroding, although it will last a long time without any protection in this respect.

The pressure of the spring upon the valve c is regulated and adjusted by the gage-screw E, which screw passes through the upper end of the spring-box D and presses against the plate c in the upper end ot' the cylinder and above the spring. As this screw is turned down it compresses the spring, so that the pressure which is transmitted through the shaft F to the val ve c can be regulated or gaged to any required degree of pressure or resistance. When the required degree is obtained the cup B is brought to place and locked by the hasp t, staple h, and lock g. It will be obvious that other forms than the padlock can be used.

I have not given dimensions, as the device will require to be made in a variety of sizes, and is increased or diminished. About the proportions given in thedrawings will be sut'- ticient. Variations will not, however, impair its working. Its operation will be readily understood from the drawings.

When the pressure in the boiler rises above the degree to which the spring a is set by the screw E the valve c will lift, when the steam will pass into the shell or case and out at I. By these Ameans I am enabled to produce a safety-valve that can be inclosed and locked up securely, the condition ot' which can be at all times tested, and that is specially adapted for use on marine engines.

Having thus described my invention, what I claim isl. The combination and arrangement of the valve c, provided with the stem F, spiral sprin g a, and set-screw E with the case D, all located within the case A, as shown and described.

2. In combination with the valve c, arranged as set forth, the lever G, arrau ged to operate as set forth.

EDVARD HAMILTON.

W'itnesses:

D. J. LYON, E. A. WEstr. 

